Torque amplifying system



Jan. 7, 1936. E. F. w. ALEXANDERSON 2,027,140

TORQUE AMPLIFYING SYSTEM Filed Nov. 2,1932 2 sheets-sheep 1.

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Invent oh:

Ehnso E Al 9 xan densbn'.

Jan. 7,1936. E. F. w. ALEXANDERSQN 1 2,027,140

TORQUE AMPL'IFYINGYSYSTEM Filed Nov. 2, 1952 2 sheets-sheet 2 Invent-or: Ehnst I? W Alexan dev's on,

1-115 AGt owney.

Patented Jan. 7',

UNITED. STATES PATENT 'roaoua. mums sr's'rau' Ernst F. w. Alexatidersoinichbnectady, 1v. 1,

assignor to General Electric Company, a comration of New-York Application November 2;- 19:2, No. 640. 14

This invention relates to torque amplifying control systems; more particularly to systems in which a load body is caused to reproduce the movements of a pilot or controlling object, and

6 it has for an object the provision of asimple, reliable and eilicient systemiof 'this character. More specifically the invention relates to systems in which a heavy load or object is caused to move in response to very minute controlling l0 forces and to follow very small movements of the controlling object, and a further pbject of this invention is the provision of a very sensitive of the current supplied to the motor.

In illustrating the invention, it is shown as embodied in a system for reproducing an indi cation and also in systems for stabilizing moving objects, such for example as ships and lights mounted on unstable platforms. V

For a better and more complete understanding of the invention, reference should now be had to the following specification and to the accompanying drawings in which Fig. 1 is a simple diagrammatical sketch of an embodiment: r the invention; Fig. 2 is 'a'vector diagram serving to aid the explanation of the op cation of the invention; and Fig. 3 is a modification.

Referring now to the drawings, a load body (not shown), is suitably connected to the shaft l0 and is driven by suitable driving means l1 lustrated as an electric motor II to reproduce the movement of a pilot or controlling object illustrated as a handwheel I! in response to the application of very small and minute forces.

The load may be any desired load such, for example, as a large electrical motion transmitting device utilized to transmit indications to a plura'lity of receiving stations responsively to actuation of the, pilot device.

As shown. the drive shaft I0 is connected to the drive shaft of the electric motor it by means of suitable driving. connections illustrated as worm gearing it. Current is supplied to the 55 armature of the motor II from suitable electr c,

the bridge controls the direction and magnitude ,as desired by varying the i positive half cycle'of the anode voltage at which [1o (cl. rat-2'39) valve apparatus ll" under the co trol of'a reactanc'e, device l5 illustrated as a reactancef bridge, themagnetic balance of ,which in turn is controlled by the pilot device l2.

The electric motor u is illustrated as adirect- 5 current type motor provided with an armature memberwhich receives direct current from the electric valve apparatus '14 to the output circuit ofwhich the armature terminals are connected by means of th'econductors l6 'andxll and-also l0 provided with a direct-current field winding it to which direct current issupplied from any suitable direct-current sourcesuch, for example, as that represented in the drawings by the two supply lines 20 to which the field winding terlfi minals are connected by means 'of the conductors 2|. a

The electric valve apparatus is illustrated as comprising a pair of electric valves 22'and- 22' for supplying direct' current in onegdirection 20 to the motor II to effect rotation thereof in a given direction and a second pair of electric 'valves-23, 24 for supplyingcurrent in the opposite direction of the motor-H to effect rotation thereof in the reverse direction. 26 Although the. electric valves may be of any suitable type they are preferably ofthe three electrodevapor electric type and, as shown, the

.pair of valves 22, 22'- are respectively, provided with plates or anodes 25 and 26, control grids 8 21 and 28 and cathodes ill and ti. 'l'ne pair of valves 23 and 24 are provid-d with similar elements as illustrated. Asis well understood, the average value of the current flowing in the'output circuit of vapor electric valves is controlled nstant during each the discharge is initiated. This may be accomplished in any suitable manner, but is preferably. accomplished by varying the phase relationship 9 between the voltages applied to the grids and to the anodes. p Alternating voltage is supplied to the anodes of the electric-valve apparatus from any suitable .5

source of alternating voltage. such, for example, 4 as that represented in the drawings by the three 7 supply lines 32 by means of a' suitable transformer, the primary winding 33 of which is connected by means of conductors 34 to the middle and lower sides of the supply source .32 and to the opposite terminals of one portion 35 of the secondary or which transformer, the anodes. and 26 of electric'valves 22 and 22' are connected fdr full-wave rectification and to the' opposits terminals of asecond portion'fl of the anodes of electric valves 23 and 24 are similarly connected for full-wave rectification.

The voltage applied to the anodes of the electric valve apparatus is represented vectorially in' Fig. 2 by the vector Ea. The. cathodes 30 and 3| of electric valves Hand 22' are illustrated as of the filamentary type and are heated to the required degree of incandescence by electric current supplied thereto by means of a .fllame'nt transformer 31, the primary winding of which is connected to the middle and lower lines of the supply source 32 by means ofconductors 38 and hand the two sections of the secondary windingof which transformer are respectively connected respectively connected by means of conductors u and to the grids 21 and 2a and alternating voltage is similarly supplied to the grids of the electric valves 23 and 24 by means of a grid transformer 46, the opposite terminals of the secondary winding of which are similarly respec tively connected to the grids of these valves as illustrated. The primary windings ofthe grid transformers 43 and 46 are'connected in series relationship with each other and with the secondary winding of the step-up grid bias transformer 41, the opposite terminals ofthe primary winding of which are respectively connected to the lower side of the supply source 32 by means of conductor 38 and to a mid-tap of the primary winding 33 of the anode transformer by means of a conductor 48. The connection of one termi- 116.1 of the grid bias transformer 41 to the.midten of the primary winding 33 of the anode supply transformer is made for the purpose of providing an initial phase displacement between the secondary winding of which 'transformer the. constitute respectively opposite points of the ,bridge, and that the points I5 and 30 similarly constitute opposite points of the bridge. The first pair of bridge points 54 and are respectively connected to the middle and bottom supply lines 32 by means of conductors 33 and 43 as illustrated whilstthesecond pair of'bridge points l55-and is connected'to the grid circuit of the electric valveapparatus; the point 33 being connected to a point 63 between the pri- 1o mary windings of the grid transformers 43 and 46 and the bridge point 60 being connected to a mid-point .64 of the secondary winding of the grid supply transformer 41. .The pair of reactance windings 53 and}! constitutingopposite l5 arms of the bridge are arranged upon a laminated core 65 which partially constitutes a magnetic circuit for these windings, whilst the pair of windings 32 and 63 is similarly arranged uponalaminated core 86 likewise partially constitut- '20 ing a magnetic circuit for these windings. The laminated core members Hand 83 are arranged in'spaced apart relationship and the magnetic circuit of both pairs of reactance windings is r completed by a laminated armature member 31 25 arranged in a central position inthe-air gap between the cores 65 and 66 and mounted for movement in opposite directions between the cores 35 and 66 and represented by thearrows in the drawings. As-shown, the cores 3! and 33 so and thearmature 61 have a tooth and slot con-' struction-and are so arranged that upon movement' ofthe armature 81, its teeth pass into the slot of one orthe other of thecore members 35 or 63 depending upon the direction of movement 35 of the armature.

- pilot device l2 by means of a supporting rod-33 voltages applied to the grids and anodes of the electric valves as illustrated vectorially in Big. 2, in which the vector Ec represents the biasvoltage supplied to the grids by the gridbias trans.-

former 41 and in which the angle between the vectors E, and Ee represents the phase angle between these voltages. when. the grid voltage is substantially in phase with the anode voltage.

maximum current flows in the output' c'ircuit of the electric valves. whilst when the grid voltage is in excess of lagging with respect to the anode-voltage. substantially zero current flows in1the output circuit. For intermediate phase j relationships. the current in" the output circuit;

has corresponding intermediatevalues. -In order to vary the phase relationship between the grid and anode voltages. a component volta e of variable magnitude and reversible polarity is supplied to the grids of the electric valve apparatus by means of the reactance bridge l3.

-As shown, this. bridge comprises a pair of re-" conductor 51;, bridge point 53, reactance coil 5|.

of t 'coils 4 netically' balanced with the result that no voltage bridgenoint 60. conductor 6l,- the reactance coili- Bland thence by conductor 32 tobrldge point 54. It will thus be seen that the points 34 and 53 upon one extremity of which it is'mounted and upon the other extremity of which is mounted the 40' third element or output gears Ill of'a mechanical differential device, the input gear II of which is fixedly mounted upon the shaft of the pilot device l2. Buitable'means illustrated as a pair-.0!

springs I2 are provided for the purpose-of cen- 3 tering the armature 31 in a mid-positionbetween.- the cores 3! and 33. When the armature member 311s in the mid-position in which it is illustrated, the reluctances of the magnetic circuit of coils-I3 and ii and the pair oinlo 2 and I3 are equal and the bridge is magexists: across the brldgepolnts and 33 and consequently-no component voltage is supplied by the/bridge to the grid circuit of the electric 53 valve apparatus. However, when the armature $1 .is moved from the mid-position toward one of the cores and away from the other; for example. toward the core 33 and away from the core. ".the reluctance or the magnetic circuit 60 o: reactance windings l3 and. is decreased whilst the reluctanceof the-magn'eticcircuit' of' reactance windings-"32 j and 33 is increased with the result that the. bridge is magnetically unbalanced and a voltage is supplied to the grid '63 circuit of the electric valve apparatus. The con nections between the bridge and the grid circuit are.so chosen that the component voltage supplied to grids-2'| and 23 is-vectorially repre-' sented by the vector. E4 substantially in phase 70' with the anode voltage Ed and the component, voltage supplied to the 'gridsof electric valves 23 and 24 is out of phase therewith and is represented by the vector Edi. The magnitude of the voltages Ed and Edi supplied to the grid 75 circuit by the bridge depends. icon the 2,027,140 a i amount example, toward thecore I. As previously exof movement. ofthe armature 81 and the resultf plained, the movement oi. the armature l1,

ant grid voltage, i. e,, the actual voltage applied to the grids is the vectorialsum of the grid bias.

voltage 1!. supplied by the"transiormer'4'l and the component voltage Ea represented by the resultant voltage E; for the pairs! valves 22;

22','and by the vector Ei'i for the other pair of valves. It will thus be seen that by increasing the'magnitude of the voltage Ed, the resultantvoltage applied to the grids of valves 22 and 22' is varied from the substantially out-oi-phase position'oi-the bias voltage Es toward the inphhse position with the vector Ea, .thereby increasing the currentsupplied by the pair of valves 22, 22 to the motor' it. On the other hand t the magnitude of this component voltage E; is decreased? the resultant voltage E; is'

nent voltage Es supplied to the grid circuit by the bridge is zero and the pair of electric valves rent to the motor II which consequently comes In a similarmanner, when the armature 61 is moved in the opposite direction from the position in which it is illustrated, the bridge I! is magnetically unbalanced in the opposite direction with the result that a voltage of opposite polarity appears across the bridge points I5 and and the component voltages represented by the vectors Ed and Ed! are. now' reversed. Consequently, the resultant or actual grid voltage now represented by the vector .Egl is moved still further toward the in-phase position with respect to the anode voltage Ec'oi electric valves 7 23 and 24, thereby the latter. and

causing them to suppLy current to the motor it in the reverse directionoi. that previously described and likewise causing the motor II to rotate in the reverse direction. I

As shown, the drive shaft of the motor Ii is connected to the second-element or. input gear With the above understanding of the apparatusand its, connection and organization in the completed system, the operation or the system Q itself will readily be understood from the detailed description which follows:

To place the system in operation the switch 14 in circuit with the primary winding "33 of the anode supply transformer is-operated to the closed position to apply voltage to the anodes o! the electric valveapparatus. The motor H is at rest and the armature 61 is constrained to the central position in which it 'is' illhstrated by means of the spring I2. The gear 13 of the difi'erential device is locked against rotation by means of the worm gearing i3 Rotation of the pilot device Reflects rotation of the input gear II of the diflerential device and consequent rota tion of the output gears 10 about the longituv dinal axis of the shaft I0 thereby moving the;

armature 61 in a direction dependent upon the direction of rotation oithe pilot device i2; {or

towards the core 66 results in energisation oi the electric valves 22 and 22' which supp cur- 1 rentto the motor II in such a direction as to I cause the shaft ii to rotate in a direction and 'by an amount dependent upon the direction and amount of movement of the pilot device 12. Hotation of the shaft i0; howeve eiiects rotation oi. the input gear II in such a diredtion'as to 10" cause the a'rmature'tl to be return'ed to the. central position, rebalance the bridge II and thereby de'energise the valves 22 and 22'Land stop the motor 'II at the instant that the rota- .tion of the shaft II is the desired amount with l'i respect to the controlling movement of the pilot device l2; Similarly, rotation ot'the pliotdevice 12 in the opposite direction eii'ccts movement of the armature 61 toward the core I! thereby unbalancing the bridge in the reverse direction, so.- energizing the electric valves 23 and 24' to supply V current to the motor ii in the reverse direction and thereby electing rotation of the'latter in the'reverse direction. This reverse rotation oi the motor ll acts through-the diii'erential gear- SIS ing to return the armature If to the central position in which the bridge is balanced; and

the valves 23, 24 and the motor ii are deenergized when the. rotation of the motoris the desired amount. with respect to the tern of the pilot. device l2.

It will thus be seen that the differential connection between the pilot device, the armature 61 and the motor it acts as a follow-up so that therotation. oi the motor and the movement 01,86

the load driven thereby follow .very closely the controlling movement of the pilot device 12 and deenergize the motor when the desired amount oi movement of the control of the load has been eiiected. This arrangement is extremely sensid0" tive and accurate and it has been determined that even as'slight a movement oithe armature member 61 as! 1/1000 of an inch from is central position causesone or the other of the pairs of electric valves to be energized and causes the motor to move the load by a proportional amount.- The system is also extremely sensitive in that pressure. applied to the pilot'device l2- by the finger tip is suflicient to move the armature Q1 and initiate operation oiv the system. In the modified iorm shown in Fig. 3, the motor 11- is supplied with alternating current from a suitable. source illustrated as an alternating currentv generator 8|, whichinturn is' driven by a dlrect -current motor 82. The generator 8| is 58 connected to the tors83. Current is supplied to the armature of -the. motor 82 by means of electric valve apparatus 84 under the control of a reactance. orm'agnetic 60 motor 'II- by meansoi 'conduc bridge I! in all respects identical with the clos tric valveapparatus and magnetic bridge previously described in-connection with ,1. I

The, operation of the driving motor. H 1.8 controlled b'y a suitable control device, such wer as ample as thesmall gyroscope 86. The gyroscope "is so mounted that it'has no freedom-oi motion'about twooiits axes, and has only limited motion about a third'axis 81. The casing of the gyroscope is connected by means oi. arod ll to 70 the armature member of the reactance bridge 85, and motion of precession oi the gyroscope in either direction is opposed by'suitable resil-- 'ient means 9i illustrated as a spring'having one extremity attached to the connecting rod 08 and 18.

contr l sysso the opposite extremity connected to the shaft of an armature member movably mounted a worm wheel 92 in mesh with a worm 93' mounted upon the drive shaft of the drivingmotor 82, In operation themovable armature member an is in the mid position between the spaced apart cores of the reactance bridge when there is no precession of the gyroscope and the spring ll serves to center the armature!!! in this midposition.

Any precession of the .gy-roscope BGisZtrans mitted through the connecting'rod 88 to the armature 90 of the bridge 85, thereby moving the armature 90 in one direction or the other and energizing the electric -valve' apparatus 84 and the motor 82 in a manner similar to that already ent updn the direction of-precession of the'gyroscope.

Since the drive shaft of the motor 82 is connected to theconnecting rod 88' through the worm gearing 92, 93 and the spring 9|, the rotation oi motor 82 reacts upon the controlby creating a force, in the spring iii, the direction of which is opposed to the force exerted by the precession of the gyroscope 86. The motor BLcontinues to run until the spring pressure counterbalances the pressure of the gyroscope.

Precession of the gyroscope in the reverse direction eflects movement of the armature 90 of the magnetic bridge in the reverse 'direction[ thereby causing the motor 82, the generator BI, and the driving motor 11 to rotate in the reverse direction.

It will thus be seen that the drivingmotor I1 is at rest only when the pressure of the spring 9| counterbalances the pressure ofthe gyroscope 86. Consequently, the total rotation of motor TI is always proportional to the precession of the gyroscope 88 and therefore when the precession ceases the gyroscope exerts no force and the spring 9| causes the armature 90 to control the electric valve apparatus 84 to bring the motor to res J ,4 Although in accordance with the provisions of the patent statutes, this invention is described as embodied in concrete form, it will be understood that the apparatus, connections, and modiilcations shown and described are merely illustrative and that the invention is not limited thereto since alterations and modifications will readily suggest themselves to persons skilled in the art without departing from the true spirit of this invention or the scope of the annexed What I claim as new and desire tosecure by Letters Patent of the United States, is:

1. An torque amplifying system comprising an electric driving motor, supply means for said motor comprising electric-valve apparatusprovided with a control grid, means for supplying a voltage tosaid grid, means for controlling said grid voltage comprising a reactance bridge connected to said grid and provided with a core" divided into two members spaced apart to provide an air gap, said air gap for controlling the magnetic bala e of said bridge, a pilot device for moving.-said armature to unbalance said bridge and-a' connection from said motor to said armature for returning said armature member to its initial position to balance said bridge.

2. A follow-up-system in which an object is driven into positional agreement with a pilot device comprising an electric driving motor for said driven object, supply means for said motor comprising electric valve apparatus provided with a control grid, means for supplying a voltage .to said grid, control means for said electric valve apparatus, comprising a reactancei-bridge connected to said grid and provided with a' pair of core rnembersaspaced apart'to provide an air gap and with a movable armature member mounted in said air gap for controlling the polarityof the voltage across said bridge, a connection-from said pilot device to said armature for effecting movement of said armature to unbalance said bridge in response to movement of said device thereby to energize saidmoton'and a connection from said motor to said armature for returning said armature to its initial position to balance said bridge and deenergize said .motor 'afterrotation thereof proportional to-the movement of said pilot device. q

3. A torque amplifying system comprising. in combination an electric driving motor, electric valve apparatus comprising atleast two electric valves for supplying current to said motor in respectively opposite directions, each of said valves being provided with a control grid, means for supplying a voltage to saidgrids, and means forcontrolling the polarity of said grid voltage comprising a plurality of reactance windings connected to forma bridge having. opposite terminals connected to said gri ds so that voltages of respectively opposite polarities are applied to said grids, at leasttwo of said windings being arranged in spaced apart relationship, an arma- -ture arranged inthe space between said windlugs and biased to a predetermined position in which said valves and said motor are deenergizedand means for moving said armature in respectively opposite directions from said predetermined position to icflect reversal of the polarities of said grid voltages to selectively energize said valves to eifect rotation of said motor in a direction dependent upon the direction of movement of said armature. p

4. A torque amplifying system. comprising in combination an electric driving motor, electric valve apparatus comprising at least two electric valves each provided with a control grid for supplying current to said motor in respeetively opposite directions, means for supplying voltage to said grids, means for controlling the magnitude and polarity of said grid voltages comprising a rreactance bridge having opposite terminals 1 connected to said grids so that voltages applied .to said grids are of opposite polarity and having two pairs of coils,'each pafr provided with magnetic circuits arranged in spaced relationship and an armature member biased to a predetermined position in said space in which said bridge is balanced and said valves are deenergized and combination. an electric driving motor, 'supply means for said motor comprising electric valve apparatus provided with a control grid, control means for said electric valve apparatus comprising a magnetic bridge connected to said grid and provided with a pair of magnetic members spaced apart to form an air gap, a movable armature member mounted in said air gap and biased to a predetermined position in which said valve apparatus and said motor are deenergized, means for applying a force to move said armature from said predetermined position to energize said valve apparatus and effect rotation of said motor, and means operated by said motor for opposing said force and returning said armature to said predetermined position to deenergize said valve apparatus and stop said motor upon an amount of rotation oi! said motor dependent upon the magnitude ofisaid force.

6. A torque amplifying system comprising in combination, an electric driving motor supply means for said motor comprising electric valve apparatus provided with a control grid, control means for said electric valve apparatus comprising a magnetic bridge connected to said grid and provided with a pair of magnetic circuits spaced apart to form an air gap, a movable armature member mounted in said air gap and biased to a predetermined position in which said valve apparatus and said motor are deenergized, means for applying a force to move said armature from said predetermined position to energize said valve apparatus and eflect rotation of said motor, and a resilient connection between said motor and said force applying means for opposing said force and returning said arma-' ture to said predetermined position to stop said motor upon a rotation proportional to the magnitude of said force.

7. A torque amplifying system comprising electric driving motor, supply means for said motor comprising electric valve apparatus provided with a control grid, means for supplying a voltage to said grid, and voltage control means for said grid comprising a magnetic bridge supplied with voltage and connected to said grid for supplying to said grid a component voltage having a predetermined phase. relation with respect to said first-mentioned voltage, and said bridge being provided with a movable armature for controlling the magnetic balance of said bridge to vary the magnitude of said component voltage and the 'phase relationship of the resultant grid voltage.

8. A follow-up system comprising an electric driving motor, supply means for said -motor comprising electric valve apparatus provided with a control grid circuit, and a reactance bridge connected to said control circuitcomprising a plurality of reactance coils, each of at least two of said coils being provided with cores ar- 5 ranged end to end and spaced apart, a movable armature arranged in the space between said cores "for controlling the magnetic balance 0! said bridge, a pilot device for effecting. movement of said armature to unbalance said bridge and energize said motor, and a connection from said motor to said armature 'for returning said armature to initial position to balance said bridge and deenergize saidmotor after rotation. thereof proportional to the movement 0! said pilot device.

9. A torque ampliiying system comprising an electric driving motor, supply means for said motor comprising electric ,valve apparatus provided with a control grid circuit andcontrol means for said valve apparatus comprising a plurality of reactance coils connected to form a bridge and having a pair of spaced apart U-shaped complementary core members, connections from said bridge to said control circuit, a

movable armature arranged in the space between said core member for controlling the balance of said bridge, a movable pilot device connected to efl'ect movement oi! said armature to unbalance saidbridge and energize said motor, and a conshaped core members arranged with their open 40- ends adjacent each other and spaced apart to provide an air gap, a plurality of reactance coils mounted on the legsof said core members and connected to form a bridge. connections from said bridge control circuits, a movable armature arranged in said air gap for controlling the balance of said bridge, a movable controldevice connected to move said armature to unbalance said bridge and energize said motor, and a connection from said motor to said armature folreturning saidarmature to balance position of said bridge thereby to deenergize said motor upon rotation proportional to the movement of said controldevice. Y

ERNST I". W. ALEXANDERSON. 68 

